package es.juanc.io;

import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;

/**
 * Convert the various newline conventions to the local platform's newline
 * convention.
 * <p>
 * 
 * This stream can be used with the Message.writeTo method to generate a message
 * that uses the local plaform's line terminator for the purpose of (e.g.)
 * saving the message to a local file.
 */
public class NewlineOutputStream extends FilterOutputStream {
	private int lastb = -1;

	private static byte[] newline;

	public NewlineOutputStream(OutputStream os) {
		super(os);
		if (newline == null) {
			String s = System.getProperty("line.separator");
			if (s == null || s.length() <= 0)
				s = "\n";
			newline = new byte[s.length()];
			s.getBytes(0, s.length(), newline, 0);
		}
	}

	public void write(int b) throws IOException {
		if (b == '\r') {
			out.write(newline);
		} else if (b == '\n') {
			if (lastb != '\r')
				out.write(newline);
		} else {
			out.write(b);
		}
		lastb = b;
	}

	public void write(byte b[]) throws IOException {
		write(b, 0, b.length);
	}

	public void write(byte b[], int off, int len) throws IOException {
		for (int i = 0; i < len; i++) {
			write(b[off + i]);
		}
	}
}
